The widow of former KGB spy Alexander Litvinenko is fighting on at the High Court to force a public inquiry into her husband's death.

Marina Litvinenko is challenging the UK Government's decision to await the outcome of a normal inquest before deciding whether there should be a wider-ranging inquiry.

Ms Litvinenko says she wants to get to "the truth" of how her husband came to die in 2006 after fleeing Russia and receiving political asylum in the UK.

He was poisoned with radioactive polonium-210 while drinking tea with two Russian men, one a former KGB officer, at the Millennium Hotel in Grosvenor Square.

His family believe he was working for MI6 at the time and was killed on the orders of the Kremlin.

Mrs Litvinenko appealed to the British public for money to finance today's case after High Court judges refused last year to protect her against a potentially ruinous costs bill of up £40,000 if she loses.

She is seeking a ruling that Home Secretary Theresa May was wrong not to order a public inquiry into her 43-year-old husband's death.

Ben Emerson QC, appearing for Mrs Litvinenko, said at a recent court hearing she was risking "almost everything she has in terms of assets she can access" by launching her application for judicial review.

Coroner Sir Robert Owen requested a public inquiry, saying that a normal inquest would be an inadequate forum to probe the alleged involvement of the Russian state in Mr Litvinenko's death.

But the Home Secretary decided that the inquest should proceed, and adopted a "wait and see" stance as to whether a public inquiry or other form of further investigation might be necessary later.

Mrs Litvinenko says she is backing the coroner's view that an inquest is unlikely to return a verdict that will reflect the truth of what happened.

Last October the Government won a legal battle to overturn the coroner's decision to reveal secret material at the proposed inquest.

Sir Robert decided to partially lift a public interest immunity (PII) certificate, arguing that disclosure of the secret material was necessary for a ''fair and meaningful'' inquest.

Government lawyers contended the documents were ''sensitive to the highest degree'' and public disclosure would damage the national interest.

Foreign Secretary William Hague won a High Court ruling that the PII material must remain secret.